The London Underground, which opened in 1863, was the world’s first underground railway system. More than 30,000 passengers tried out the Tube on the opening day and it was hailed by the Times as “the great engineering triumph of the day”. Pictured - William Gladstone on an inspection of the first underground line.

Now Tokyo’s metro system carries 8.7 million passengers a day. It has introduced women-only carriages during the morning rush hours to provide “a sense of security”. Its Subway Manners guidebook advises passengers to set their mobile to silent mode and refrain from talking during the ride.

Although Moscow’s metro opened in 1935, the first plans date back to the Tsarist era. According to Pravda, Joseph Stalin was the first passenger and the driver had to practise driving a train with a Stalin dummy in it for several days before the actual trip. Pictured - Muscovites admire the new Taganskaya station in 1950.

Plans to build the Beijing metro system were first discussed in the early 1950s, but preparations were halted in 1961 as a result of the Great Famine. When the subway plan was first discussed, the Chinese capital had a population of only three million. Pictured - the Beijing subway in the 1980s.

When the subway was first built the then-premier, Zhou Enlai, said: “Beijing is building the subway purely for defence reasons. If it was for transport, purchasing 200 buses would solve the problem.” However, Beijing’s subway is now one of the busiest in the world, carrying nearly 10 million passengers a day.

Seoul’s 40-year-old subway is the currently the world’s longest system. It provides 4G and wireless broadband coverage in all stations and trains. The seats are climate-controlled and automatically heat up in winter. Its cleanliness and ease of use has also earned it the reputation of being one of the world’s best systems.